JSFiddle - React, Tailwind, and code Playground

HTML

<select name="category">
    <option value="A">A</option>
    <option value="B">B</option>
    <option value="C">C</option>
</select>

<input id="auto" data-id="A" type="search"/>

JavaScript

$('select').change(function(){
      $('#auto').attr('data-id',$(this).val())
})


 $('#auto').autocomplete({
    delay: 1000,
    source: function( request, response ) {  
            alert($(this.element).data('id'))
            return false
    }
 })